1. Field of the Invention
The present invention relates to a light reflecting plate, a method of manufacturing the same, and a light reflecting device using the light reflecting plate, more particularly to a light reflecting plate with excellent light reflection characteristics, a method of manufacturing the same, and a light reflecting device such as a mirror duct that illuminates the interior of a room by guiding sunlight indoors by the light reflecting plate.
2. Description of the Related Art
Conventionally, as a light reflecting device equipped with a light reflecting plate, a mirror duct that guides sunlight indoors to use it as illumination is known (Japanese Patent Laid-open No. Sho58-93101, Japanese Patent Laid-open No. 2000-149627). It takes in sunlight from a daylighting section, transmits the light that was taken in by reflection through a light ray guiding tube, and emits light indoors from a light emitting section.
Further, in the mirror duct described in Japanese Patent Laid-open No. 2000-149627, a light-diffusing device of a special shape is installed on a light path inside the light guiding section. The light-diffusing device diffuses and reflects light that was made incident into the mirror duct to make light ray in the mirror duct evenly spread. Note that the document also discloses an example where diffusing film is inserted halfway the light path.
However, in the mirror duct disclosed in Japanese Patent Laid-open No. Sho58-93101, spread of light ray flux of sunlight to be taken in is substantially limited to the size of a daylighting section 1 as illustrated in FIG. 9, and the light ray flux is reflected and transmitted by the mirror-finished inner wall of a light ray guiding tube 2 while maintaining the spread when the light was taken in, so that light reflected and transmitted through the light ray guiding tube 2 is outputted from the light emitting section intensively to one or a plurality of areas, and there is a problem that uneven illumination occurs.
Now, there is a problem that glare increases as the inner wall of the light ray guiding tube 2 is mirror-finished in order to increase light reflectance by regular reflection.
The method disclosed in Japanese Patent Laid-open No. 2000-149627 where the diffusing film is provided for the mirror duct has a problem that light intensity generally attenuates by several tens percent when light passes through the diffusing film although uneven illumination and glaring phenomenon are relaxed.
Further, a method in which a diffusing device of light is specially provided has a problem of taking much installing cost.